Valium belongs to a lesson of drug called benzodiazapines, which are used to treat insomnia, anxiety and as anesthetic adjuncts for treating convulsions. Prozac belongs to a class called selective seretonin-reuptake inhibitors, and impact brain chemistry.
SSRIs are believed to gain the extracellular level of the neurotransmitter serotonin by inhibiting its reuptake into the presynaptic cell, increasing the level of serotonin available to bind to the postsynaptic receptor. They have varying degrees of selectivity for the other monoamine transporters, with pure Ssris having only weak affinity for the noradrenaline and dopamine transporter.
They are usually used as antidepressants, anti-anxiety agents or as a treatment for premature ejaculation. Both drugs can create physical dependency when used long term and should not be abruptly discontinued due to withdrawal syndrome.
One is a benzodiasapene (sp) while the other is a selective seratonin reuptake inhibitor (ssri).
Benzos are habit forming and tend to relax you or make you high. Benzos include Librium, Xanax, Valium, Atavian, etc.
SSRIs tend to just calm your anxiety with no high.